Valve actuation mechanism including valve lash adjustment means

ABSTRACT

A lash adjustor for the valve actuating mechanism of an internal combustion engine having an overhead camshaft comprising an adjustable rocker arm fulcrum. A fulcrum stud is slidingly received within a bore formed in the cylinder head. A spring biases the stud to a position of maximum protrusion to permit automatic positioning of the stud for lash adjustment. A clamp may be tightened about the stud to fix its position relative to the cylinder head.

United States Patent Stirrat Apr. 29, 1975 VALVE ACTUATION MECHANISM mar/.239 1/1935 Lochrane .v 123/9052 INCLUDING VALVE LASH ADJUSTMENT 2,4181 10 4/l947 Burkhardt.... H l23/9U.45 MEANS 15643902 8/l95l Houser .7 Ill/90.45 2923.282 2/1960 White .v Q3/9045 [75] Inventor: George F. Stir-rat, Bloomfield Hills 3.542.001 11/1 70 Linc A i i i 4 t v l33/ v 3 Mi h 3,779.58? 12/1973 Racine it 285/323 n3] Asslgnee: 5 Motor company Dembom Primar Eran1im'rManuel A. Antonakas 1c Assistant Examiner-Daniel J. OConnor {22] Filed: May 2, 1973 Artur-n0 Agent. or Firm-Roger E. Erickson; Keith L. [2]] Appl. No; 356,524 Zemh'mg [57] ABSTRACT 7 7 7 lshl l23/90's2 74/52 'icgg j A lash adjustor for the valve actuating mechanism of [51] Int Cl b an internal combustion engine having an overhead camshaft comprising an adjustable rocker arm full58] Flow of Crum. A fulcrum stud is slidingly received within a 2815,755 bore formed in the cylinder head. A spring biases the stud to a position of maximum protrusion to permit automatic positioning of the stud for lash adjustment. l56] References cued A clamp may be tightened about the stud to fix its po- UNITED STATES PATENTS sition relative to the cylinder head. 1.577970 3/l926 Hosterman l23/90.43 1.583.335 5/[926 Borschcl 123 9052 Clam 3 D'awmg figures [I A [31." l 1/ 1/ M g 1/ 42 H u l J w 7"' t l u 1; I

VALVE ACTUATION MECHANISM INCLUDING VALVE LASI-I ADJUSTMENT MEANS BACKGROUND AND SUMMARY OF THE INVENTION Clearance is required between the elements of an internal combustion engine valve actuation mechanism to permit thermal expansion and to reduce element wear. A means commonly utilized in prior art engines to adjust the lash between the elements of the valve actuation mechanism is a threaded fulcrum stud received in a threaded bore in the engine cylinder head. The stud is rotated with a wrench until a feeler gauge may be inserted properly between the rocker arm and the camshaft.

This invention provides a valve lash adjustor which is not dependent upon the subjective feel of the gauge inserted between the rocker arm and the camshaft. It also provides a valve lash adjustment means in which the clearance may be simply adjusted by positioning a gauge between the camshaft and the rocker arm and by loosening and retightening the clamp means. The invention further provides lash adjustment means which assures uniformity in lash adjustment among the several valve operating mechanisms of a multicylinder engine. Still further, the invention provides valve lash adjustment means adaptable for use in currently used overhead camshaft engines and which is economical to produce and reliable in operation.

Valve lash adjustment means constructed in accordance with this invention include a bore formed in the cylinder head of the engine slidingly receiving a fulcrum stud. A compression spring is engagable with the received end of the stud and urges the protrusion of the stud from the bore. A clamp means is threadedly engagable with the cylinder head and frictionally engagable with the stud.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I of the drawings is a transverse cross sectional view with portions in elevation of a valve actuating mechanism incorporating this invention.

FIG. 2 is a cross sectional view taken along line 2-2 of FIG. 1.

FIG. 3 is a cross sectional view of an alternate embodiment of an adjustable fulcrum.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1 of the drawings. reference numeral 11 refers to a portion of a cylinder head of an internal combustion engine having an overhead camshaft l3. Reciprocably mounted within a bore 15 formed in the cylinder head is an intake or exhaust valve 17 having a protruding stem portion 19. A spring retainer assembly 21 is secured to the end of the valve stem by the aid of a split conical collar 23. The collar has a radially inwardly extending annular flange cooperating in the conventional manner with an annular groove formed in the valve stem. A coil spring 25 is compressed between the retainer 21 and a spring seat 27 formed in the cylinder head. An oil seal 29 is positioned about the valve stem boss 31 and slidingly engages the valve stem.

A second bore 33 is formed in the cylinder head 11 which slidingly receives a fulcrum stud 3S and a compression spring 37. Bore 33 opens into an enlarged threaded bore 39 which receives a threaded insert 41.

The insert includes a hexagonal head portion 43 rotatable by means ofa conventional open end wrench. The insert has an inner bore 45 and a tapered or conical surface 47. Received within the bore 45 and the conical surfaces 47 of the insert is a split collar 49 having outwardly directed conical surfaces 5l-which correspond to the inwardly facing conical surfaces 47 of the insert. The inner surfaces 53 of the split collar are cylindrical of a radius substantially equal to that of the fulcrum stud stem 35.

The fulcrum stud 35 includes a spherical head portion 55 and a pair of annular flanges defining an annular groove 57. Positioned between the end 58 of the valve stem 19 and the head 55 of the fulcrum stud is a rocker arm 61. The rocker arm includes a spherical socket portion 63 that receives the spherical surface 55 of the fulcrum stud to provide a universal pivot. Spring clip assembly 65 is engagable with the rocker arm and groove 57 of stud 35 to resiliently bias the rocker arm into engagement with the head of the pivot stud and with the end of the valve stem.

The overhead camshaft I3 is mounted to the cylinder head for rotation about a predetermined axis 66. Each cam surface 67 engages an upwardly directed pad portion 69 of the rocker arm 61.

To adjust valve lash, a feeler gauge of the desired thickness is inserted between the base cam surface 67 and the rocker arm pad 69. The insert 41 is turned with a wrench so that it moves upwardly relative to the cylinder head, loosens the split collar 49 and releases the fulcrum stud 35. The stud is pushed upwardly by the force of compression spring 37 until no significant clearance exists between elements of the valve actuation mechanism. The insert is then tightened so that the split collar 49 once again grips the pivot stud and fixes its position relative to the cylinder head. A washer 71 is positioned about the pivot stud at the base of the threaded bore 39 and engages the inner ends of the split collar 49 to prevent gouging of the cylinder head.

DESCRIPTION OF AN ALTERNATE EMBODIMENT An alternate embodiment of the lash adjustor is shown in FIG. 3. In this embodiment the threaded insert 73 has a pair of conical portions 75 and 77. The split collar 79 has corresponding conical surfaces SI and 83. As the insert is drawn into the threaded bore 39 of the cylinder head the conical surfaces interact forcing the split collar members radially inwardly to grip the pivot stud 35 and to fix the position of the stud relative to the cylinder head.

Modifications and alterations will occur to those skilled in the art which are included within the scope of the following claims.

I claim:

1. In an internal combustion engine having a cylinder head,

a bore formed in the cylinder head,

a rocker arm fulcrum stud slidingly received within said bore and having one end protruding therefrom,

spring means engagable with said stud urging the protrusion of said stud from said bore,

clamp means threadedly engagable with said cylinder head and frictionally engagable with said stud,

said clamp means being movable to release and to secure said stud relative to said cylinder head.

2. in an internal combustion engine according to claim I, said spring means comprising a compression spring received within said bore.

said spring acting between the base of said bore and the received end of said stud.

3. ln an internal combustion engine according to claim 1, said clamp means comprising an insert member positioned about said stud. said insert member having a threaded portion coaxial with said bore threadedly received within said cylinder head, said insert member including an inwardly directed conical surface.

split collar means having outwardly directed conical surfaces corresponding to and engagable with said insert member conical surface. said split collar means having inwardly directed cylindrical surfaces corresponding to and cooperating with said stud.

abutment means formed in said cylinder head about said bore limiting the axial displacement in one direction of said split collar means.

4. In an internal combustion engine, a cylinder head. a valve having a valve stem reciprocally mounted within said cylinder head, a fulcrum stud mounted within said cylinder head, a camshaft rotatably mounted to said cylinder head, a rocker arm having one end pivotably mounted on said stud, the other end positioned at the end of said valve stem and an intermediate portion slidingly engagable with said camshaft,

a bore formed in said cylinder head.

said stud being slidingly received within said bore,

spring means engagable with stud urging the protrusion of said stud from said bore.

clamp means threadedly engagable with said cylinder head and frictionally engagable with said stud, said clamp means being movable to release said stud or to secure said stud relative to said cylinder head.

5. In an internal combustion engine according to claim 4, said spring means comprising a compression spring received within said bore.

said spring acting between the base of said bore and the received end of said stud.

6. In an internal combustion engine according to claim 4, said clamp means comprising an insert member positioned about said stud. said insert member having a threaded portion coaxial with said bore threadedly received within said cylinder head, said insert member including an inwardly directed conical surface.

split collar means having outwardly directed conical surfaces corresponding to and engagable with said insert member conical surface. said split collar means having inwardly directed cylindrical surfaces corresponding to and cooperating with said stud.

abutment means formed in said cylinder head about said bore limiting the axial displacement in one direction of said split collar means.

7. In an internal combustion engine according to claim 6, said spring means comprising a compression spring received within said bore,

said spring acting between the base of said bore and the received end of said stud.

8. ln an internal combustion engine according to claim 4, said bore opening into a threaded bore formed in said cylinder head, said threaded bore being concentric with said first mentioned bore and having a relatively larger diameter.

said clamp means comprising an insert member positioned about said stud and having a portion thread edly received within said threaded bore. said insert member including an inwardly directed conical surface,

split collar means positioned within said insert member and about said stud, said split collar means having outwardly directed conical surfaces corresponding to and engagable with said insert member conical surface and having inwardly directed cylindrical surfaces corresponding to and cooperating with said stud.

said insert member being rotatable in one direction to tighten said split collar means about said stud and in the other direction to release said split collar means from about said stud and to permit said stud to slide within said first mentioned bore.

9. In an internal combustion engine according to claim 8, said spring means comprising a compression spring received within said bore.

said spring acting between the base of said bore and the received end of said stud.

10. In an internal combustion engine according to claim 4, said clamp means comprising an insert member positioned about said stud, said insert member having a threaded portion conical with said bore and threadedly received within said cylinder head. said insert member including a pair of inwardly directed conical surfaces separated by an inwardly directed cylindrical surface.

split color means having a pair of outwardly directed conical surfaces corresponding respectively to and engagable with said insert member conical surfaces, said split collar means having inwardly directed cylindrical surfaces corresponding to and cooperating with contiguous surfaces of said stud.

H. The combination of claim 10, said spring means comprising a compression spring received within said bore,

said spring acting between the base of said bore and the received end of said stud. 

1. In an internal combustion engine having a cylinder head, a bore formed in the cylinder head, a rocker arm fulcrum stud slidingly received within said bore and having one end protruding therefrom, spring means engagable with said stud urging the protrusion of said stud from said bore, clamp means threadedly engagable with said cylinder head and frictionally engagable with said stud, said clamp means being movable to release and to secure said stud relative to said cylinder head.
 2. In an internal combustion engine according to claim 1, said spring means comprising a compression spring received within said bore, said spring acting between the base of said bore and the received end of said stud.
 3. In an internal combustion engine according to claim 1, said clamp means comprising an insert member positioned about said stud, said insert member having a threaded portion coaxial with said bore threadedly received within said cylinder head, said insert member including an inwardly directEd conical surface, split collar means having outwardly directed conical surfaces corresponding to and engagable with said insert member conical surface, said split collar means having inwardly directed cylindrical surfaces corresponding to and cooperating with said stud, abutment means formed in said cylinder head about said bore limiting the axial displacement in one direction of said split collar means.
 4. In an internal combustion engine, a cylinder head, a valve having a valve stem reciprocally mounted within said cylinder head, a fulcrum stud mounted within said cylinder head, a camshaft rotatably mounted to said cylinder head, a rocker arm having one end pivotably mounted on said stud, the other end positioned at the end of said valve stem and an intermediate portion slidingly engagable with said camshaft, a bore formed in said cylinder head, said stud being slidingly received within said bore, spring means engagable with stud urging the protrusion of said stud from said bore, clamp means threadedly engagable with said cylinder head and frictionally engagable with said stud, said clamp means being movable to release said stud or to secure said stud relative to said cylinder head.
 5. In an internal combustion engine according to claim 4, said spring means comprising a compression spring received within said bore, said spring acting between the base of said bore and the received end of said stud.
 6. In an internal combustion engine according to claim 4, said clamp means comprising an insert member positioned about said stud, said insert member having a threaded portion coaxial with said bore threadedly received within said cylinder head, said insert member including an inwardly directed conical surface, split collar means having outwardly directed conical surfaces corresponding to and engagable with said insert member conical surface, said split collar means having inwardly directed cylindrical surfaces corresponding to and cooperating with said stud. abutment means formed in said cylinder head about said bore limiting the axial displacement in one direction of said split collar means.
 7. In an internal combustion engine according to claim 6, said spring means comprising a compression spring received within said bore, said spring acting between the base of said bore and the received end of said stud.
 8. In an internal combustion engine according to claim 4, said bore opening into a threaded bore formed in said cylinder head, said threaded bore being concentric with said first mentioned bore and having a relatively larger diameter, said clamp means comprising an insert member positioned about said stud and having a portion threadedly received within said threaded bore, said insert member including an inwardly directed conical surface, split collar means positioned within said insert member and about said stud, said split collar means having outwardly directed conical surfaces corresponding to and engagable with said insert member conical surface and having inwardly directed cylindrical surfaces corresponding to and cooperating with said stud, said insert member being rotatable in one direction to tighten said split collar means about said stud and in the other direction to release said split collar means from about said stud and to permit said stud to slide within said first mentioned bore.
 9. In an internal combustion engine according to claim 8, said spring means comprising a compression spring received within said bore, said spring acting between the base of said bore and the received end of said stud.
 10. In an internal combustion engine according to claim 4, said clamp means comprising an insert member positioned about said stud, said insert member having a threaded portion conical with said bore and threadedly received within said cylinder head, said insert member including a pair of inwardly directed conical surfaces separated by an inwardly directed cylindrical surface, split color means having a pair of outwardly directed conical surfaces corresponding respectively to and engagable with said insert member conical surfaces, said split collar means having inwardly directed cylindrical surfaces corresponding to and cooperating with contiguous surfaces of said stud.
 11. The combination of claim 10, said spring means comprising a compression spring received within said bore, said spring acting between the base of said bore and the received end of said stud. 